I tried to work this out per pig, but it really depends on if you buy food and bedding in bulk (sacks of feed, whole bales of hay etc) or at the pet shop in smaller quantities.
A sack of food lasts my 12 about a fortnight - so two sacks a month, say £20
I use shavings, £6 per bale, 2 bales a month = £12
Hay - I buy in large sacks as I don't have room for a bale and don't want mice - £1 sack, sack a week or so = £5
Veg - I live in the country and lots of people save me their peelings etc. so I buy a sack of horse carrots, £1.50 a month plus I spend about £5 a week in the supermarket still = £6.50
I also buy Graze On dried grass at £8 a bale but this lasts a while - say £4 mth
So, not including vets bills, wormer etc. I reckon 12 cost me £47.50 a month, or about £4 per pig.
Um, and I was basing this on 12 pigs but I now have (running out of fingers and toes to count on!) 18.
Hmmm, I wish I hadn't done the maths now! £4 per pig sounds much better. Think of it like that. Not including toys, treats, sickness, housing, etc. etc. etc.!
Sophie